The sun returned to Spa-Francorchamps for the afternoon Formula One practice after a very wet morning on opening day of the Belgian Grand Prix.

Despite a punctured right rear Pirelli tyre that caused Sebastian Vettel time in the pits, the German did lay down the fastest lap on Friday with a time of 1:49.331; ahead of his Red Bull Renault teammate Mark Webber by 0.059 of a second.

The three-time World Champion commented: “We don’t know what happened when I got the puncture in P2. We lost the rear right, very suddenly, so we need to have a look – Pirelli is working on finding out why it happened."

Webber said, “It’s always tricky here to get the right set up for the whole lap, so we took the opportunity today to try some different ones."

Third fastest was Lotus Renault’s Romain Grosjean with his best lap at 1:50.149. His teammate, Kimi Raikkonen was in test mode toward the end of practice due to being one of the teams who elected to sit out for most of the morning due to slippery track conditions.

"It wasn’t that easy as we found it quite hard to make the tyres work the way we would like them to which meant that in the car the feeling might not have been so good, but timing-wise it was actually okay. The car felt pretty good and we’ll work on this baseline to continue to improve. We’ll wait to see what the weather will have in store for us," said Grosjean.

Raikkonen commented on his being under the weather the past few days: “I feel fine here today and the car was okay. It could have been a bit better, but it wasn’t a disaster either so for sure we can improve a bit more for tomorrow."

The Finn’s best lap of 1:50.318 was 0.987 of a second off the pace Vettel.

Felipe Massa was fourth fastest for the Ferrari team with a 1:50.164.

On a slippery Spa-Francorchamps circuit earlier in the day, Fernando Alonso nearly had the track to himself for most of the session. The Spaniard laid down the fastest lap with a time of 1:55.198 in his Ferrari. For the afternoon dry session, Alonso’s best was a 1:50.510 which placed him seventh best on the dry circuit,

Fifth fastest was Jean-Eric Vergne whose best lap in his Toro Rosso Ferrari was a 1:50.253. The Frenchman is one two team drivers that hope to move up to the Red Bull team next year. His teammate Daniel Ricciardo could only muster a 1:51.447 lap time, and he is the one rumored to take the seat of Webber when the Australian moves to Porsche’s new prototype for the 24 Hours of Le Mans and the World Endurance Championship next year.

The shock of the day belongs to two teams: Mercedes team and McLaren-Mercedes. The fastest of the four drivers was Sergio Perez with a 1:50.536 with the eighth best lap of the day. Not far off his pace was Nico Rosberg with a 1:50.601.

Further down the order were Jenson Button and Lewis Hamilton. In his Mercedes, Hamilton was 12th behind both Force India drivers. The other Briton was further back in 15th.

However, Friday practice is more like a test day with short and long runs, adjustments that the teams engineers make, setup of the racing machine based on the track, and in this case, Spa is known for constant changes -- mainly the weather.

The real indication of who might earn the pole position could come during the final practice.